Box 1. Running Win 7, connected to the Internet via Eth0. Has one wireless network adapter and one another ethernet adapter (say, Eth1).

Box 2. Running Win XP, has one ethernet adapter.

I'd like to share Internet connection of the Box 1 with Box 2 via cable and have box 1 also sharing the Internet with other wireless devices. I don't want to buy any additional hardware. Is it possible?

3 Answers
3

I'm going to start by strongly recommending simply buying an ISR instead of doing it the way you wish, it'll be so much less hassle, and better performance and convenience to boot (that and they're not too expensive). That said, what you want can be done.

A crossover cable is the same as the standard cabling you're used to (probably cat5 UTP), but with one change. In a standard "Straight-through" cable, on the inside, there are 8 wires going from end to end. The same is true of a crossover cable, but instead wires are crossed in such a manner that the wires meant for sending traffic and receiving traffic synch up on each end. See the Wikipedia article for more info, if you care.

Note that the colours in this picture do actually match up to real life. Take a close look at the rj-45 connector on your Ethernet cable, if it is transparent, you will be able to see by the order of coloured wires what kind of cable it is!

Which you can purchase from pretty much any computer shop, or make yourself.

First off, make sure both computers are in the same workgroup.
Windows xp: Right click "My Computer" -> Properties, then click the "Computer name" tab. Click "Change" and name a workgroup. Reboot.
Win7: Use the start menu search to find the change workgroup name dialogue, and set it to the same as the XP box. Reboot.

Now hook the two machines together using the Ethernet crossover cable.

Next, share the internet connection:
On the Win 7 box, search in the start menu for "View network connections". Right click on the internet connection, and select "properties", followed by clicking the "sharing" tab. Check "Allow other network users to connect through this computer’s Internet connection" and click OK.

Now both machines should be able to share files and an internet connection. As for the wireless, I've never done it - I'm not actually sure that you can use a wireless NIC as an access point.

As a note, some, I stress some, ethernet ports can automatically use a straight-through as a crossover cable. I have done this before with varied success. It seems the more modern ethernet controllers have this ability.
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Nathan AdamsMay 19 '10 at 20:41

I want to add on my thoughts -
Windows ICS (Internet Connection Sharing), which is what Dmatig suggesting you setup can only allow you to "share" the internet with one other interface. So, you can share the internet with Box 2, but you can't with other wireless clients.

As far as wireless clients is concerned - if you have an AP all you need to do is connect to the AP and share eth0 with the wireless interface and everyone on the AP gets internet access (you need to disable DHCP on the AP of course).
Or you can create an ad-hoc network and basically use it to create an "AP-less" wireless network. Of course, Box 2 will not get internet access.

What you should do, buy a cheap wireless router and plug a cable from eth1 to the WAN on the AP. Then share eth0 with eth1, and plug box 2 into the AP. This covers all physical clients AND wireless.